The use of yeasts whose metabolism is generally employed for the purpose of manufacturing high value-added molecules such as ethanol, flavors, short and long-chain fatty acids is well known in the field of biotechnology. These processes are known as anaerobic fermentation.
Furthermore, it is known that when these yeasts are placed under aerobic conditions, they modify their metabolism. The substrate carbon is then used only for the production of biomass. Yeasts "breathe", that is to say they produce water and carbon dioxide, while multiplying. In the publication "Water Science and Technology", Vol. 19, RIO page 11-21, 1987, Huyard et al. showed that the aerobic metabolism of yeasts could be used to remove the carbon pollution from waste water. However, to this end, it is necessary to select pure yeast strains or collection strains, cultivate them in a fermenter so as to produce a yeast sediment and then to inoculate with this yeast sediment the effluent which it is desired to depollute. However, the success of this operation depends on the adaptation of these pure strains to the substrate. Now, the latter is often very heterogeneous, that is to say it consists of a multiplicity of molecules. The result is that, because most of the yeasts used are not adapted to this substrate, the period of acclimation or adaptation of these yeast strains to the substrate is thereby all the longer and more unpredictable.
In the effluents from wine cellars, which are obtained for example by the discharge of the lees from wine vats, there are many yeasts which are especially adapted to the substrates obtained from the processing of grape musts. In these lees, the yeasts are maintained under anaerobic conditions.